Communicating computer-aided detection results in a standards-based medical imaging environment

ABSTRACT

A method, system, and method of doing business in a standards-based medical imaging environment is described in relation to the communication of computer-aided detection (CAD) results among devices, with one embodiment relating to the DICOM standard. CAD results are fixably integrated into the pixels of a secondary image derived from a source image, and the secondary image is transferred using a DICOM Secondary Capture Image Information Object Instance (SCI-IOI). The DICOM SCI-IOI is transferred to a viewing workstation, whereby a clinician can open, manipulate, and view the secondary image in a side-by-side comparison with the source image or derivative images thereof. Advantageously, CAD results are communicated to the clinician in a DICOM-conforming manner independent of whether the viewing workstation supports standard DICOM accommodations, such as CAD Structured Report Information Object Instances (CAD SR-IOIs), for the type of CAD results that need to be presented. Optionally, an equipment information entity identifier in a CAD SR-IOI and/or the SCI-IOI can be modified to change or shield the identity of the manufacturer of the CAD processing unit.

FIELD

This patent specification relates to the computer-aided detection ofabnormalities in medical images. More particularly, this patentspecification relates to communicating and displaying computer-aideddetection results in a medical imaging environment that operates, atleast in part, according to a standard medical imaging communicationsprotocol such as the DICOM standard.

BACKGROUND

The industrial standards process has generally been recognized as apermissible form of cooperation among otherwise competing enterprises.By promoting operational compatibility and apples-to-apples comparisonof products and services, the standards process can lead to enhancedconsumer choice, greater competition, and increased technologicalinnovation. However, the possibility exists that a larger enterprisehaving an established market presence might only selectively activatecertain features of an agreed-upon standard in order to obtain anadvantage over market entrants or smaller competitors. For example, thelarger enterprise might choose to impose certain conditions, such asbundling conditions, on the sale of a key system component beforeactivating the supposedly “standard” features within that key systemcomponent. Purchasers of the key system component are thereby “forced”to purchase any complementary system components from that same largerenterprise, much to the detriment of market entrants and smallercompetitors who relied on the existence of the agreed-upon standard indeveloping their own complementary components. At least in part, thepresent patent specification relates to an instance of this “selectivestandards activation” scenario that might be found, either presently orprospectively, in the medical imaging industry.

The DICOM standard (Digital Imaging and Communications in Medicine) isdefined and maintained by the National Electrical ManufacturersAssociation, and is directed to providing a common framework for theacquisition, transmission, archiving, retrieval, and presentation ofmedical images of the human body and related patient data for a varietyof imaging modalities and environments. As discussed in Horii, “ANontechnical Introduction to DICOM,” RadioGraphics 1997:1297-1309 (RSNA1997), the DICOM standard is highly adaptable and continues to grow toaccommodate advances in medical imaging technology. According to Horii,the fact that many of the medical imaging equipment manufacturers areglobal corporations has sparked considerable international interest inDICOM, with both European and Japanese standards organizations adoptingsubstantial portions of DICOM. The DICOM standard is maintained andextended by the DICOM Standards Committee, which is an international,multi-specialty committee.

Currently, the DICOM standard consists of sixteen published parts, PS3.1-2003 through PS 3.16-2003, describing different aspects of the DICOMstandard. By way of example, the first published part is a 20-pagedocument that can be fully cited as “National Electrical ManufacturersAssociation, Digital Imaging and Communications in Medicine (DICOM), PS3.1-2003 Part 1: Introduction and Overview, (NEMA 2003).” This documentcan more briefly be cited as “PS 3.1-2003: Introduction and Overview,”“PS 3.1-2003,” or, most simply, “PS 3.1,” it being understood that thelatter is a reference to the current year, a past year, or a group ofyears according to the context. Among other published parts of the DICOMstandard relevant to the present disclosure are the third part, “PS3.3-2003: Information Object Definitions,” the fourth part, “PS3.4-2003: Service Class Specifications,” the sixth part, “PS 3.6-2003:Data Dictionary,” and the sixteenth part, “PS 3.16-2003: Content MappingResource.”

Recent additions to the DICOM standard have been made to accommodate thefield of computer-aided diagnosis (CAD) in which specialized computerprograms analyze medical images to detect anatomical abnormalities, orlesions, therein. Sometimes used interchangeably with the termcomputer-aided diagnosis are the terms computer-aided detection,computer-assisted diagnosis, or computer-assisted detection. The outputsof CAD systems, generally referred to herein as CAD results, are sets ofinformation sufficient to communicate the locations of anatomicalabnormalities, or lesions, in a medical image, and can also includeother information such as the type of lesion, degree of suspiciousness,and the like.

Examples of a mammography CAD system are presented in U.S. Pat. No.5,729,620 and U.S. Pat. No. 5,917,929, which are incorporated byreference herein. An example of a chest CAD system is presented inWO02/056240, which is incorporated by reference herein. It is to beappreciated that, although particular references to mammography andchest CAD system are provided infra, the scope of the preferredembodiments includes any of a variety of CAD systems that receive 2D or3D medical images of a body part and detect, automatically or withmanual assistance, anatomical abnormalities therein. Examples includecolon CAD systems, bone CAD systems, and other CAD systems.

It is to be further appreciated that although particular reference tox-ray mammography and chest CT imaging modalities is provided infra, thescope of the preferred embodiments includes any of a variety of imagingmodalities that, either presently or prospectively, (i) are amenable toCAD analysis, and (ii) are accommodated by the DICOM standard (or othermedical imaging standard) from a CAD perspective. Prospective examplesmay include magnetic resonance imaging (MRI), positron emissiontomography (PET), single-photon emission computed tomography (SPECT),and ultrasound, as well as less conventional medical imaging modalitiessuch as thermography, electrical conductivity-based modalities, etc.

Among the recent CAD-related additions to the DICOM standard areadditional Information Object Definitions (IODs), including theMammography CAD Structured Report (SR) IOD and the Chest CAD SR IOD (PS3.3, Annexes A.35.5, A.35.6). The Mammography and Chest CAD SR IODs areused to convey the detection and analysis results of mammography andchest CAD systems, respectively. The content may include textual and avariety of coded information, numeric measurement values, references tothe image data from which the CAD results were obtained, and spatialregions of interest within that referenced image data. TheMammography/Chest CAD SR IODs accommodate data not only for presentationto the clinician, but also data that may be solely for use in subsequentmammography/chest CAD analyses.

The contents and formatting of the Mammography and Chest CAD SR IODs areconstrained according to CAD-related additions to PS 3.16 in the form oftemplates, and context groups for the coded terminology. For example,the Mammography CAD SR IOD is constructed according to the “Template ID(TID) 4000 Mammography CAD Document Root Template” which, in turn, canimplicate subordinate templates as needed, the subordinate templateshaving names such as “TID 4001 Mammography CAD OverallImpression/Recommendation Template,” “TID 4009 Mammography CADIndividual Calcification Template,” “TID 4010 Mammography CADCalcification Cluster Template,” and “TID 4011 Mammography CAD DensityTemplate.” Likewise, the Chest CAD SR IOD is constructed according tothe “TID 4100 Chest CAD Document Root Template” which, in turn, canimplicate subordinate templates such as “TID 4101 Chest CAD FindingsSummary Template,” “TID 4102 Chest CAD Composite Feature Template,” and“TID 4105 Chest CAD Descriptors.” Further information on the Mammographyand Chest CAD SR IODs are provided in PS 3.3 at Annexes L and M,respectively.

Other additions to the DICOM standard made to accommodate CAD includethe addition of specified Service-Object Pair (SOP) Classes. As known inthe art, a SOP Class is a union of a specific set of DICOM MessageService Elements (DIMSEs) and a related IOD which completely defines aprecise context for communication. For accommodation of CAD, there arenow two Structured Reporting Storage SOP Classes—the Mammography CAD SRSOP Class and the Chest CAD SR SOP Class—instances of which transferMammography CAD SR Object Instances and Chest CAD SR Object Instances,respectively, from one device to another. (PS 3.4, Annexes B.5, O).There is also an additional Structured Reporting Media Storage SOP Classfor each of the Mammography and Chest CAD SR IODs, instances of whichare interchange and offline storage of Mammography CAD SR ObjectInstances and Chest CAD SR Object Instances, respectively (PS 3.4, AnnexI). Finally, there are also additional SOP Class Unique Identifiers(UIDs) for the additional SOP Classes (PS 3.6, Annex A).

For clarity of presentation herein, where convenient, an informationobject (IO) or information object instance (IOI) shall be referred toindependently of the SOP Class or SOP Instance of which they may be apart. The formation or presence of the appropriate SOP Class or SOPInstance can be inferred from the identity of the IO or IOI beingdescribed, together with the action being taken and/or the descriptivecontext. Also for clarity of presentation herein, where convenient,treatment of IOs or IOIs is without regard to their classification asnormalized or composite, it being understood that their appropriatetype, as well as the appropriate corresponding DIMSEs, SOP Classes, SOPInstances, etc., can be likewise inferred.

A typical configuration for a DICOM-based medical imaging system havingCAD analysis features includes an image acquisition system (IAS), a CADprocessing unit, and a viewing workstation (VWS). The IAS, CADprocessing unit, and VWS are usually connected by a network, mostcommonly a TCP/IP based network, having sufficient bandwidth toaccommodate transfer of medical images thereamong. The IAS is coupled toa physical image acquisition device (e.g., digital x-ray unit, CT unit,etc.) and receives the raw image data therefrom. The IAS populates theattributes of the relevant image information object, e.g., the DigitalMammography X-Ray Image Information Object or the CT Image InformationObject, to form an instance of that object, which is genericallyreferred to herein as a Source Image Information Object Instance(SI-IOI), it being understood that “Source” is substituted for theparticular modality (“Digital X-Ray”, “CT”, etc.) as the preferredembodiments described herein extend to a variety of imaging modalities.

The SI-IOI is then transferred to the CAD processing unit, whichperforms CAD analysis on the digital image(s) contained in the SI-IOI.Based on the results of the CAD analysis, the CAD processing unitconstructs the relevant CAD SR Information Object Instance (CAD SR-IOI),e.g., the Mammography CAD SR-IOI or the Chest CAD SR-IOI. The CAD SR-IOIis then transferred to the VWS. Depending on the particular systemimplementation, the original SI-IOI created by the IAS may betransferred directly from the IAS to the VWS or, alternatively, theoriginal SI-IOI can accompany the CAD SR-IOI from the CAD processingunit to the VWS.

The VWS generates a display of the digital source image(s) contained inthe SI-IOI, which are usually of diagnostic quality. The VWS alsorenders the CAD information contained in the CAD SR-IOI for presentationto a clinician. Rendering generally refers to the extraction of relevantCAD information from the CAD SR-IOI and the display of that informationin a manner that facilitates clinician analysis of the medical image(s)upon which that CAD SR-IOI is based. In one known system, the VWSsuperimposes CAD markers and other CAD annotations derived from the CADSR-IOI over the original digital images in the SI-IOI responsive to theclinician's pressing of a single toggle button. This provides a fast andeasy method of offering a “second look” opportunity for the clinician inorder to facilitate early detection of anatomical abnormalities.

A problem can arise, however, for market entrants or smaller enterprisesseeking to market CAD processing units alone, their customers purchasingIAS and VWS units from other suppliers. More particularly, eitherpresently or prospectively, a large enterprise having a substantial VWSmarket presence might harness that VWS market presence to bolster itsshare in the CAD processing unit market. In one scenario, this could beattempted by disabling the VWS from receiving and rendering CAD SR-IOIs,using either a software key or other disabling mechanism, unless the VWScustomer also purchases their CAD processing unit from the VWS supplier.This effectively prevents the customer from purchasing their CADprocessing unit from another source, because they would not be able toreceive and view the results from the competing CAD processing unit in aDICOM-conforming manner. Rather, the customer would be required to viewtheir CAD results in more awkward and workflow-inhibiting ways, such asby using paper CAD result printouts, or by placing an entirelyadditional CAD viewing workstation next to their VWS. This represents anundesirable scenario for the customer and, of course, for the providerof the competing CAD processing unit.

Another problem can be found in relation to new CAD processingcapabilities as they arise, regardless of whether they are developed bya market entrant, a smaller enterprise, or a large existing enterprise.In particular, the ability of the DICOM standard to accommodate new CADprocessing capabilities, in the form of appropriate CAD SR IODs, forexample, can lag behind the introduction of the new CAD processingcapabilities themselves. By way of example, while the DICOM standard maypresently include Mammography CAD SR IODs and Chest CAD SR IODs, it maynot presently include colon CAD SR IODs, bone CAD SR IODs, or, moregenerally, “anatomy X” SR IODs. By way of further example—althoughexpected to be a less common scenario—a currently established CAD SR IODmight not yet accommodate a brand new form of CAD processing ability forthat particular anatomical part, such as upon the discovery of newanatomical patterns shown to signify a future likelihood of disease. Anenterprise wanting to market CAD processing units capable of the newestCAD capabilities would again be required to have their customers use thenew machines in awkward and workflow-inhibiting ways, because existingthe DICOM-conforming VWS units would not be capable of receiving andrendering the CAD results therefrom. Alternatively, the new CADprocessing units and the existing VWS units would need private mutualmodifications, most likely of the non-conforming variety, in order toaccommodate transfer and rendering of the CAD results, which isgenerally undesirable in the long term.

Another problem can arise in that, even if the VWS manufacturer is notpurposely attempting to disable CAD-related communication features,their VWS can simply be incompetently or erroneously designed, tested,and/or implemented such that structured reporting communications withthe CAD processing unit are hindered. Also, for any of a variety ofreasons, a given VWS installation may not be sufficientlybackward-compatible or forward-compatible as needed to properly achievethe needed structured reporting communications with the CAD processingunit.

One known DICOM-based medical imaging system, developed prior to theadoption by the DICOM Standards Committee of general structuredreporting including the above CAD SR IODs, uses the Radio TherapyStructured Set (RTSS) to communicate CAD results from a CAD processingunit to an VWS or other DICOM system. See R2 Technology, Inc., “DICOMConformance Statement M1000-DM, V2.3A” (February 2001). However, asstated in a warning therein, “The use of RTSS by this device does notconform to the DICOM standard, as the data in the RTSS object is notradiotherapy related.” Accordingly, use of the RTSS to communicate CADresults from a CAD processing unit entails non-conforming operation ofboth the CAD processing unit and the VWS (or other destination device),which is generally undesirable in the long term.

Accordingly, it would be desirable to provide a method of doing businessin which a CAD processing unit provider can integrate its CAD processingunits into existing medical imaging systems in a DICOM-conformingmanner, even where a VWS in the medical imaging system has had one ormore of its DICOM CAD accommodations disabled for that CAD processingunit provider.

It would be further desirable to provide a medical imaging system inwhich CAD results are communicated, in a DICOM-conforming manner, from aCAD processing unit to a VWS for presentation to a clinician, even wherethe VWS cannot or will not properly receive or process any DICOM CADstructured reports, and/or a particular kind of DICOM CAD structuredreport, from the CAD processing unit.

It would be further desirable to provide a medical imaging system inwhich CAD results are communicated, in a DICOM-conforming manner, from aCAD processing unit to a VWS for presentation to a clinician, even wherethere is currently no mechanism to describe those CAD results using thecurrent CAD accommodations of the DICOM standard, that is, when theDICOM CAD accommodations have not been amended or appended to cover theparticular kind of CAD processing performed by the CAD processing unit.

SUMMARY

A method and system for communicating computer-aided detection (CAD)results in a DICOM-based medical imaging environment is provided,wherein a source image is analyzed by a CAD processing unit to generatethe CAD results, the CAD results including CAD markers and CADannotations, wherein the CAD markers are fixably integrated into thepixels of a secondary image derived from the source image, and whereinthe secondary image is incorporated into a DICOM Secondary Capture ImageInformation Object Instance for transfer to a destinationDICOM-conforming device. Preferably, the destination DICOM-conformingdevice is a viewing workstation, whereby a clinician can open, view, andmanipulate the secondary image containing the CAD markers in aside-by-side comparison with the source image or derivative thereof. Inanother preferred embodiment, CAD annotations such as text-basedidentifiers, analyses, comments, and/or suspiciousness metrics are alsofixably integrated into the pixels of the secondary image.Advantageously, CAD results are communicated to the clinician in aDICOM-conforming manner independent of whether the viewing workstationsupports standard DICOM CAD accommodations, such as CAD StructuredReport Objects, for the particular type of CAD results. Likewise, CADresults are communicated to the clinician in a DICOM-conforming mannereven if the DICOM standard itself has not been amended or appended toaccommodate the particular kind of CAD results.

In one preferred embodiment, the source image is contained within aSource Image Information Object Instance, the Source Image InformationObject Instance being identified by a patient ID, a study instance UID,a series instance UID, and other information that allows uniqueidentification thereof. The CAD processing unit includes the patient IDand the study instance UID into the Secondary Capture Image InformationObject Instance. The Source Image Information Object Instance may betransferred to the viewing workstation from the CAD processing unit or,alternatively, may be transferred to the viewing workstation fromanother DICOM device such as an image acquisition system. Based on thepatient ID and the study instance UID contained in the Secondary CaptureImage Information Object Instance, the viewing workstation matches theSource Image Information Object Instance therewith. By manual,semi-automated, or automatic means the clinician is notified of thepresence of the Secondary Capture Image Information Object Instancecontaining the secondary image. The user can view, resize, and otherwisemanipulate the secondary image containing the fixably integrated CADresults on the user display of the viewing workstation. Advantageously,provided that the viewing workstation supports DICOM Secondary CaptureObjects, no re-programming or other modification of the viewingworkstation itself is necessary to accommodate this functionality.

In another preferred embodiment, the input to the CAD processing unit isa digital x-ray image that has been scanned and digitized from an x-rayfilm. When presented to the CAD processing unit, the digital x-ray imagemay optionally be in a non-DICOM conforming format. In such case, theCAD processing unit constructs a DICOM-conforming Source ImageInformation Object Instance, as well as a related Secondary CaptureImage Information Object Instance that includes the secondary imagecontaining the fixably integrated CAD results, for forwarding to theviewing workstation in a DICOM-conforming manner. Alternatively, thedigital x-ray image and the CAD results may be forwarded to an adaptingprocessor that constructs the appropriate DICOM-conforming Source ImageInformation Object Instance and Secondary Capture Image InformationObject Instance, which are then forwarded to the viewing workstation.

In another preferred embodiment, a method of doing business is providedin a standards-based medical imaging environment comprising a firstenterprise having an established market presence for viewingworkstations, the first enterprise disabling one or more CAD resultaccommodation features of a standard medical imaging communicationsprotocol if integrated with CAD processing units from a secondenterprise, wherein the second enterprise causes its CAD processingunits to fixably integrate its CAD results into the pixels of asecondary image type supported by the standard medical imagingcommunications protocol, the secondary image type not being specifiedfor CAD results. Preferably, the medical imaging communications protocolis the DICOM standard, and the secondary image type corresponds to theSecondary Capture Image Information Object defined by the DICOMstandard.

In another preferred embodiment, in the event that the viewingworkstation is designed to be capable of receiving and processing CADStructured Report Information Object Instances for the CAD processingcapability in question, but where such capability has been disabled fora particular target CAD processing unit manufacturer, the CAD processingunit manufacturer designs its CAD processing unit to generate a CADStructured Report Information Object Instance having a modifiedequipment information entity identifier. In particular, the equipmentinformation entity identifier is assigned values not corresponding tothe target CAD processing unit manufacturer, but rather to a differententity, whereby the viewing workstation receives and processes the CADStructured Report Information Object Instance as usual, since it is notapparent that it actually came from that target CAD processing unitmanufacturer. In one preferred embodiment, the equipment informationentity identifier is assigned to a value extracted from the Source ImageInformation Object Instance. In another preferred embodiment, theequipment information entity identifier corresponds to the viewingworkstation manufacturer itself. In another preferred embodiment, in theevent that the viewing workstation goes so far as to disable SecondaryCapture Image Information Object Instances from the target CADprocessing unit manufacturer, an equipment information entity identifiercontained in each Secondary Capture Image Information Object Instance islikewise modified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a medical imaging system including a computer-aideddetection (CAD) processor according to a preferred embodiment;

FIG. 2 illustrates steps for CAD results communication in a DICOMenvironment according to a preferred embodiment;

FIG. 3 illustrates a viewing workstation displaying a secondary imagehaving fixably integrated CAD markers, the secondary image beingdisplayed side-by-side with source medical images from which the CADresults were derived or derivative viewing images derived from thesource medical images;

FIG. 4 illustrates a viewing workstation displaying two secondary imageshaving fixably integrated CAD markers, the secondary images beingdisplayed side-by-side with source medical images from which the CADresults were derived or derivative viewing images derived from thesource medical images;

FIG. 5 illustrates steps in a method of doing business according to apreferred embodiment;

FIG. 6 illustrates a secondary image including fixably integrated CADmarkers and CAD annotations according to a preferred embodiment;

FIG. 7 illustrates a medical imaging system including a CAD processingunit and an image reference library according to a preferred embodiment;and

FIG. 8 illustrates a method of doing business including steps for CADresults communication in a DICOM environment according to a preferredembodiment.

DETAILED DESCRIPTION

FIG. 1 illustrates a medical imaging system 100 according to a preferredembodiment including an image acquisition system (IAS) 108, a CADprocessing unit 110, and a viewing workstation (VWS) 112 coupled to anetwork 114. The network 114 may comprise a local area network (LAN), ametropolitan area network (MAN), a wide area network (WAN), or generallyany network capable of communicating images among the IAS 108, CADprocessing unit 110, and VWS 112. It is to be appreciated that the IAS108, CAD processing unit 110, and VWS 112 may be contained in the samebuilding, distributed across a metropolitan area, or may even be locatedin different states or continents depending on the particularimplementation of the medical imaging system 100. Preferably, thenetwork 114 supports the TCP/IP protocol, which is used as the transportprotocol for the DICOM standard.

Coupled to IAS 108 in FIG. 1 is a digital x-ray mammography unit 102 anda computed tomography (CT) unit 104. However, as indicated by the“other” medical imaging modality element 106, the preferred embodimentsare readily extended to any of a variety of present or prospectivemedical imaging modalities, such as MRI, PET, SPECT, ultrasound, x-raytomosynthesis, thermography, electrical conductivity-based modalities,and other modalities. For clarity of description, a particular exampleof digital x-ray mammography, and CAD processing related thereto, isdescribed, it being understood that the scope of the preferredembodiments is readily extended to Chest CT as well as these otherimaging modalities. It is also to be appreciated that IAS 108 may itselfbe a distributed system, may be integrated with one of the imaging units102-106 into a monolithic image acquisition device, or may alternativelybe separated therefrom by large distances and coupled via a network,without departing from the scope of the preferred embodiments.

Also shown in FIG. 1 is a conceptual diagram of four Source ImageInformation Object Instances (SI-IOIs) 116 being transferred from theIAS 108 to the CAD processing unit 110 over the network 114. Each SI-IOI116 comprises identifying information including a patient ID, a studyinstance UID, and a series instance UID, as well as other informationthat uniquely identify that SI-IOI. For digital x-ray mammography, in atypical scenario in which a patent visits a clinic on a given day andgets the four standard views taken (LCC, LMLO, RCC, RMLO), there areactually four distinct SI-IOIs created, one for each view. These fourSI-IOIs typically have the same patient ID and study instance UID but,depending on the particular IAS manufacturer, they might not have thesame series instance UIDs.

Likewise, for a typical scenario in chest CT imaging, there aretypically many distinct SI-IOIs created, one for each tomographic sliceobtained, all having the same patient ID and study instance UID butpossibly having different series instance UIDs depending on the IASmanufacturer. For ultrasound and MRI, it is more common that there be asingle SI-IOI containing all of the related ultrasound or MRI sliceimages, which is termed a multi-frame SI-IOI. However, it is to beappreciated that the preferred embodiments described herein areapplicable to any of these situations and other situations, with theterm SI-IOI (e.g., SI-IOI 116) being used herein to refer to any of thefollowing, unless otherwise indicated: a lone single-frame SI-IOI, agroup of related single-frame SI-IOIs, a lone multi-frame SI-IOI, or agroup of related multi-frame SI-IOIs, or any combination thereof.

Preferably, as indicated in FIG. 1, the SI-IOI 116 is also sent directlyfrom the IAS 106 to the VWS 112, although this can vary according to thedesired configuration. If not sent from the IAS 108, the SI-IOI 116 canbe forwarded from the CAD processor 110 along with a DICOM SecondaryCapture Image Information Object Instance (SCI-IOI) 118. It is to beappreciated that other devices, such as storage devices or otherauxiliary devices, may be included along the data paths shown in FIG. 1,and also that many different timing schemes (real-time transfer,non-real-time transfer) can be implemented without departing from thescope of the preferred embodiments. One example of an alternativeconfiguration is illustrated in FIG. 7, infra, wherein information isoptionally transferred among two or more of the system components bycompact disks, DVDs, or other tangible storage media.

It is to be further appreciated that digital image(s) in the SI-IOI 116can be modified, filtered, or otherwise manipulated by the IAS 108 priorto being sent to the VWS 112, or may be manipulated along the path fromIAS 108 to VWS 112 by an intermediate device (not shown), resulting inone or more of what are termed herein derivative viewing images. Asknown in the art, the derivative viewing images would most often becontained in separate Image Information Object Instances than the SI-IOI116, but having the same patient ID and study instance UID, and wouldarrive separately at the VWS 112. Alternatively or in conjunctiontherewith, the source image(s) and/or derivative viewing image(s) may bemanipulated by the VWS 112 itself prior to display.

FIG. 2 illustrates steps taken by the CAD processing unit 110 accordingto a preferred embodiment. At step 202, the SI-IOI 116 is received fromthe IAS 108. At step 204, CAD analysis is performed thereon. In the caseof digital x-ray mammography, for example, the CAD processing unit wouldextract a digital image contained in the SI-IOI 116 and search forsuspicious breast masses, microcalcification clusters, or otherabnormalities therein that may be evidence of breast cancer. At step206, the CAD processing unit fixably integrates CAD markers into pixelsof a secondary image derived from one or more of the source images.

The secondary image comprises an image of at least a portion of theanatomical part contained in the source image. The secondary image ispreferably a flat image, and the CAD markers are “burned in” to thepixels of the flat image near the lesion locations. Each pixel locationthat is part of a CAD marker actually loses it pixel value (or, in thecase of a color image, values) because that pixel was forcibly turned topure black, pure white, or some other pixel value according to the CADmarking scheme. Advantageously, the VWS could never “detect” that thesecondary image actually contains CAD markers, absent the unlikely eventthat intelligent “marker-detection algorithms” were put in place by theVWS manufacturer. Thus, using this preferred embodiment, a CADprocessing competitor can effectively combat a situation such as thatdescribed supra in which a VWS manufacturer attempts to shut out thatCAD processing competitor by deactivating formal DICOM CAD-accommodatingfeatures of their VWS if it is coupled to a CAD processing unit fromthat CAD processing competitor.

Even in the absence of such a contentious competitive/anticompetitiveenvironment, the SCI-IOI containing the secondary image can be used tocommunicate newly developed CAD result types that the current CADaccommodations of the DICOM standard have no mechanism to convey.Indeed, in one preferred embodiment, the SCI-IOI containing thesecondary image can be sent in addition to the standard CAD SR-IOI, andthe VWS can both (i) render the CAD SR-IOI and (ii) allow the user todisplay and manipulate the secondary image contained in the SCI-IOI. TheSCI-IOI containing the secondary image can also be used if the relevantCAD SR-IOIs cannot be used due to design failures, lack of backward- orforward-compatibility, or any of a variety of other anomaloussituations.

At step 208, the CAD processing unit fixably integrates or “burns” otherCAD-related annotations, such as textual notes or alphanumeric lesionsuspiciousness levels, into the pixels of the secondary image. Thus, thepixel locations corresponding to CAD annotations and CAD markersirretrievably lose their underlying image data. For example, if a givenpixel location happens to be at a location corresponding the dot in the“i” of a textual annotation, that underlying image value is lost andreplaced by a zero (for black) or other fixed value.

At step 210, the Secondary Capture Image Information Object Instance(SCI-IOI) 118 is created that contains the secondary image. Depending onthe nature of the SI-IOI 116, the CAD processing algorithms, and/or thenature of the desired outcomes, there may be more than one SCI-IOI, andindeed there may be many separate SCI-IOIs depending on how manydifferent annotated images are desired. Each SCI-IOI, however, shouldcontain the patient ID and the study instance UID of the SI-IOI 116necessary for the VWS or other destination device to match that SCI-IOIwith the corresponding source image(s) and/or derived viewing image(s).The Referenced Image Sequence or Source Image Sequence attribute can bepopulated in the SCI-IOI, with the SOP Class UID, SOP Instance UID, andFrame Number of the one or more SI-IOIs from which the SCI-IOI wasderived. Although described in terms of using the patient ID and studyinstance UID to match the secondary image of SCI-IOI 118 with the sourceimage of SI-IOI 116 and/or derivative viewing image, the scope of thepreferred embodiments is not so limited, and includes any of a varietyof other matching scenarios sufficient to match up these image, as couldbe readily implemented by one skilled in the art in view of the presentdisclosure.

At step 212, the SCI IOI 116 is transferred to the VWS 112, or otherdestination device, such as a storage device. Optionally, as discussedsupra, at step 214 the SI-IOI 116 is also transferred from the CADprocessing unit to the VWS 112.

FIG. 3 illustrates an example of a display of a viewing workstation(VWS) 302 that may be used in the system of FIG. 1, comprising a leftmonitor 304 and a right monitor 306. The VWS 302 is displaying, by wayof example and not by way of limitation, one of a variety of differenthanging protocols for viewing the source medical image(s)—and/orderivative viewing image(s)—along with the secondary image(s) containingthe CAD results. Left monitor 304 displays source RCC and LCC images 308and 310, respectively, while right monitor 306 displays source RMLO andLMLO images 312 and 314, respectively. Alternatively or in conjunctiontherewith, any of the images 308-314 may comprise derivative viewingimages computed from the source images, as described supra. Included onboth monitors is “other” space that could be used for appropriate usercontrols or notifications (not shown), which include a notification,preferably iconic, to the clinician that an SCI-IOI is available. Uponclicking the icon or otherwise invoking the SCI-IOI, the user ispresented with the secondary image 316, which comprises at least oneimage of at least a portion of the anatomical part being displayed inany of images 308-314, and which includes fixably integrated CAD markers318 and 320 indicating a suspicious density and a suspiciousmicrocalcification cluster, respectively. In accordance with commonlyprovided VWS features, the user is permitted to shift the differentwindow locations around and resize them as needed.

Preferably, the secondary image 316 is of lower resolution, generallylower quality, and/or smaller size than the original images 308-314,although the scope of the preferred embodiments is not so limited.Because it should only be used as a “second look,” and should not be thesole basis of a diagnosis, the secondary image 316 should not need to beof equal or superior quality to the original images 308-314. Moreover,as an inferior-quality image, the secondary image 316 will not tempt theclinician to use it as a primary diagnosis tool, and also takes up lessstorage space and is faster to transmit over the network 114. However,it is to be appreciated that in some alternative embodiments thesecondary image could be of diagnostic quality without departing fromthe scope of the preferred embodiments. In the preferred embodiment ofFIG. 3, the secondary image 316 is a single, flat image file comprisingfour quadrants containing minified versions of the original imageaccording to the hanging protocol shown.

FIG. 4 illustrates an example of a display of a viewing workstation(VWS) 402 that may be used in the system of FIG. 1, comprising elements304-314 similar to those in the VWS 302 of FIG. 3, supra, but comprisingtwo secondary images 416 a and 416 b showing CAD markers 418 a and 418 bfor a suspicious density, and showing CAD markers 420 a and 420 b for asuspicious microcalcification cluster, according to the hanging protocolshown. In this preferred embodiment, the secondary images 416 a and 416b are incorporated into separate SCI-IOIs for transfer from the CADprocessing unit 110 to the VWS 112. The clinician is provided with twoseparate notification icons and can separately open and manipulate thesecondary images. In another preferred embodiment (not shown), there canbe four different secondary images provided in four different SCI-IOIs,each showing a single view of the breast, and so on.

FIG. 5 illustrates steps in a method of doing business in astandards-based medical imaging environment, with particular applicationto a CAD processing unit manufacturer that is not also a direct providerof VWS units. At step 502, facts are gathered to determined whether thecustomer's chosen VWS supports the CAD-accommodating features of theDICOM standard, such as the Mammography CAD SR IOD in the case of x-raymammography, or such as the Chest CAD SR IOD in the case of chest CT.These facts can be gathered by reviewing the DICOM Conformance Statementof the VWS, which is required for all devices purported to at leastpartially conform to DICOM. Alternatively or in conjunction therewith,the facts for step 502 can be gathered by empirical testing ofoff-the-shelf version of the VWS, or by examining other productliterature.

In another preferred embodiment, the determination can be dynamicallymade by the CAD processing unit 110 itself. Each time the CAD processingunit 110 establishes a DICOM association with the VWS, negotiation ofaccepted SOP Classes and Transfer Syntaxes (i.e., Presentation Context)is a required part of the association negotiation. The Service ClassUser (SCU—in this case, the CAD processing unit 110) requests a list ofpresentation contexts in an Association Request, and the Service ClassProvider (SCP—in this case, the VWS 112) responds with accepted/rejectedfor each presentation context in the list, in an Association Acceptanceor Rejection response. In this manner, the CAD processing unit canautomatically determine whether the VWS 112 supports the relevant CAD SRIOD.

If it is determined at step 504 that the relevant CAD SR IOD is indeedsupported by the VWS, then after receiving the SI-IOI and doing the CADprocessing at step 506, the CAD processing unit generates at step 508 aninstance of the relevant CAD SR Information Object Instance (CAD SR-IOI)and, at step 510, transfers it to the VWS. The CAD SR-IOI includes thesame patient ID and study UID as the SI-IOI, but will usually have adifferent series UID. Optionally, at step 512, the original IIOIreceived by the CAD processing unit is also transferred to the VWS.

However, if it is determined at step 504 that the relevant CAD SR IOD isnot supported by the VWS (or has not yet been defined), then at step 514the customer is informed that the CAD processing unit will be providingCAD results encapsulated within SCI-IOIs at the VWS. This can be donemanually by placement in the CAD processing unit user manual orliterature. Alternatively, this can be done as part of the marketing,sales, or customer training process. Even in the event that theclinician is not advised prior to VWS use, it is possible that thepresence of an SCI-IOI notification icon will cause them to open theicon to learn of the SCI-IOI contents. Steps 516-520 proceed in a mannersimilar to steps 202-212 of FIG. 2 for generating and transferring theSCI-IOI containing the secondary image having fixably integrated CADannotations.

According to one preferred embodiment, the steps 502-520 are carried outdynamically for every case by automatically performing the conformanceinquiry at step 504. This allows the CAD processing unit provider toavoid the need to make changes to the software of the unit in the eventthat the capabilities of the VWS are changed for business or technicalreasons by the VWS manufacturer. This would be particularly advantageousfor a scenario in which a newer or different CAD processing capability,not currently accommodated by the DICOM standard, is introduced into themarket. In this case, once the DICOM Standards Committee has appended oramended the DICOM standard appropriately, the CAD processing unitmanufacturer can program that relevant CAD SR IOD (and related changes)into its CAD processing units. Then, after the VWS manufacturer has“caught up” with the new technique, the CAD processing unit canautomatically switch over from the Secondary Capture Image IOI method tothe relevant CAD SR IOD method without requiring further effort orvigilance by the CAD processing unit manufacturer. Thus, adaptation canbe achieved by system configuration rather than fixed software release.

FIG. 6 illustrates an example of another secondary image 602 accordingto a preferred embodiment. The secondary image 602 comprises one or moreimages 604 of at least a portion of the anatomical part that wascontained in the source image of the SI-IOI, and further comprises a“burned in” CAD marker 606. Also “burned in” to the secondary image 602is (i) a graphical symbol 608 indicating the source of origin of the CADprocessing unit used to analyze the source image, (ii) an annotationtext field 610 identifying key information about the patient and the CADsoftware version, and (iii) a result key 612. The result key 612 shows a“1” indicating that the clinician should look for a single CAD marker.The result key 612 shows a solid frame around a triangle to communicatethat the microcalcification detection algorithm of the CAD processingunit terminated properly, and shows a solid frame around an asteriskshape to communicate that the mass detection algorithm of the CADprocessing unit terminated properly. These frames would be dotted linesfor abnormal CAD algorithm termination. Notably, the graphical andtextual information is not stored in ASCII or other symbolic format, butrather is “burned in” or fixably integrated into the pixel values of thesecondary image 602.

FIG. 7 illustrates a medical imaging system 700 according to a preferredembodiment, similar to the medical imaging system 100 of FIG. 1, supra,further comprising a VWS 704 not connected to the network 114, andfurther comprising a reference library database 706 coupled to the CADprocessing unit 110. As indicated in FIG. 7, information such as theSI-IOIs and SCI-IOIs is optionally transferred among two or more of thesystem components by physical movement of compact disks or DVDs 702 orother tangible storage media, rather than by using network 114. An“other” destination component 708 is included to signify that there area variety of downstream components (paper printers, film printers,storage devices, etc.) that may use the secondary images/SCI-IOIswithout departing from the scope of the preferred embodiments.

The reference library 706 is configured to store large amounts ofhistorical mammographic data (or other image data) from a variety ofpatients, preferably with known diagnoses. As part of its CADalgorithms, the CAD processing unit 110 can compare a current suspiciouslocation with similar anatomical abnormalities taken from the historicaldata. The historical data can be from the current patient and/or a largepopulation of patients. An example of a reference library is presentedin US 2002/0043729 A1, published on Nov. 22, 2001 (Giger et. al.), whichis incorporated by reference herein. According to a preferredembodiment, the secondary image of the SCI-IOI further comprises severalframes and/or mini-frames of data taken from the reference library inany of a variety of configurations as described in US 2002/0043729 A1,all of this information being “burned” or fixably integrated into thesecondary image. In one preferred embodiment, the secondary imagecomprises an overall picture of the anatomical part in question, and aplurality of mini-frames at its periphery with close-ups of suspiciouslocations, images from the reference library 706, etc. This is but oneexample of how, in accordance with a preferred embodiment, an advancedCAD-related diagnostic technique or capability can be effectivelycommunicated to the clinician, independent of whether the DICOM standarddoes, or does not, support such CAD-related abilities in its CADaccommodations as currently specified.

FIG. 8 illustrates a method of doing business including steps for CADresults communication in a DICOM environment according to a preferredembodiment. As used herein, a target CAD manufacturer is a CADprocessing unit provider that another enterprise having an establishedpresence in the VWS market is trying to “shut out” by disabling CADcommunications therewith. At step 802, it is determined whether the VWSpossesses the fundamental ability to receive and process CAD StructuredReport Information Object Instances for the CAD processing capability inquestion. If not, then at step 810, it is determined whether the VWS hasdisabled SCI-IOIs if they were generated from the target CADmanufacturer, and if not, then at step 814 an SCI-IOI constructedaccording to FIG. 2 and having “burned in” CAD markers and annotationsis transmitted to the VWS. If at step 810 it is determined that the VWSmanufacturer has gone so far as to disable SCI-IOIs generated from thetarget CAD manufacturer, then at step 812 the SCI-IOI is modified, ifnecessary, to ensure that the equipment information entity identifiereither (i) does not contain any reference to a Secondary CaptureDevice's Manufacturer, Manufacturer's Model Name, or Software Version,or (ii) if it does contains one or more of such identifiers, that theseidentifiers do not implicate the target CAD manufacturer. The DICOMspecification makes the above three specific entries optional in theSCI-IOI.

As used herein, a device is still DICOM conforming even if there is someindirection involved in a source-of-origin identifier of an IOI or SOPInstance, as these indirections are business rather than technically ormedically oriented. This is distinguished from the non-conforming RTSSexample presented supra, in which the RTSS was used for an entirelydifferent medical purpose than that for which it was specified.

If, at step 802, it is determined that the viewing workstation is indeedfundamentally capable of receiving and processing CAD Structured ReportInformation Object Instances for the CAD processing capability inquestion, it is then determined at step 804 whether such capability hasbeen disabled for the target CAD manufacturer. If not, then at step 808,a CAD SR-IOI having its equipment information identifier populated withthe identity of the target CAD manufacturer (who, it has just beendetermined, is not a actually a “target” in this particular instance) istransferred to the VWS. But if so, then at step 806 the equipmentinformation identifier is modified such that at least its (mandatory)Manufacturer identifier is redirected or spoofed to that of anothermanufacturer,.and optionally the (optional) Manufacturer's Model Nameand/or Software Version identifier is also similarly redirected. In onepreferred embodiment, the Manufacturer identifier is spoofed to that ofthe IAS if the IAS is not the same as the target CAD manufacturer, andin another preferred is spoofed to that of the VWS manufacturer itself.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that theparticular embodiments shown and described by way of illustration are inno way intended to be considered limiting. By way of example, althoughdetailed supra in terms of the DICOM standard, the preferred embodimentsare readily applicable to any medical imaging standard having a firstchannel, object, or service definition directed to CAD resultscommunication and a second channel, object, or service definitiondirected to accommodating secondary image types. By way of furtherexample, in an optional preferred embodiment, the VWS can be programmedto completely skip over any case in which the number of CAD markers iszero, such that the clinician does not even see the source, secondary,or derivative viewing images at all, whereby the clinician workload andmedical enterprise costs are substantially reduced. The number of CADmarkers generated can be determined by accessing the appropriate CADSR-IOI attribute, and/or by running an optical character recognition(OCR) algorithm on the result key 612 and/or or a marker detectionalgorithm on the overall secondary image.

By way of even further example, while described above in terms ofsoftcopy workstations, the scope of the preferred embodiments alsoincludes making hardcopies of the secondary images on paper or film,archiving of the SCI-IOIs, and generally any of a variety of possibledownstream uses for the secondary images/SCI-IOIs. Therefore, referenceto the details of the preferred embodiments are not intended to limittheir scope, which is limited only by the scope of the claims set forthbelow.

1.-34. (canceled)
 35. In a computer-aided detection (CAD) processingunit, a method for detecting and communicating anatomical abnormalitiesaccording to a predetermined type of CAD processing capability,comprising: receiving a first medical image of an anatomical part of ahuman body; processing the first medical image to detect anatomicalabnormalities therein according to said predetermined type of CADprocessing capability; determining whether a destination device iscapable of receiving and processing DICOM CAD Structured ReportInformation Object Instances (CAD SR-IOIs) for said predetermined typeof CAD processing capability from the CAD processing unit; if saiddestination device is capable of receiving and processing CAD SR-IOIsfor said predetermined type of CAD processing capability, performing thesteps of: incorporating information relating to said detected anatomicalabnormalities into the CAD SR-IOI for said predetermined type; andtransferring said CAD SR-IOI to said destination device; and if saiddestination device is not capable of receiving and processing CADSR-IOIs for said predetermined type of CAD processing capability,performing the steps of: forming a second medical image including atleast a portion of the anatomical part, said second medical image havingCAD markers fixably integrated therein at pixel locations correspondingto said detected anatomical abnormalities; incorporating said secondmedical image into a DICOM Secondary Capture Image Information ObjectInstance (SCI-IOI); and
 36. The method of claim 35, wherein saidpredetermined type of CAD processing capability is x-ray mammographyCAD, and wherein said CAD SR-IOI is a Mammography CAD Structured ReportInformation Object Instance.
 37. The method of claim 35, wherein saidpredetermined type of CAD processing capability is chest CAD, andwherein said CAD SR-IOI is a Chest CAD Structured Report InformationObject Instance.
 38. The method of claim 35, wherein said predeterminedtype of CAD processing capability is bone CAD or colon CAD.
 39. Themethod of claim 35, said destination device being a viewing workstation(VWS), wherein said step of determining is performed automatically bysaid CAD processing unit as part of a DICOM association negotiationbetween said CAD processing unit and said VWS.
 40. The method of claim35, said destination device being a viewing workstation (VWS), whereinsaid step of determining is performed manually by review ofdocumentation corresponding to said VWS or by compatibility testingbetween said CAD processing unit and said VWS.
 41. A method forcomputer-aided detection (CAD) of anatomical abnormalities, comprising:receiving a first medical image of an anatomical part of a human body;processing the first medical image to detect anatomical abnormalitiestherein; forming a second medical image including at least a portion ofthe anatomical part, said second medical image having CAD markersfixably integrated therein identifying said detected anatomicalabnormalities, wherein said second medical image is of a standard DICOMimage type not specified for CAD results; and transferring said secondmedical image to a destination device according to the DICOM protocol.42. The method of claim 41, wherein said second medical image comprisesa DICOM Secondary Capture image.
 43. The method of claim 41, whereinsaid destination device comprises a DICOM-conforming device selectedfrom the group consisting of: a viewing workstation, an image archivingsystem, and a hardcopy printer.
 44. The method of claim 41, wherein saidreceiving said first medical image comprises receiving a Source ImageInformation Object Instance from a DICOM-conforming source device, theSource Image Information Object Instance comprising said first medicalimage.
 45. The method of claim 41, wherein said receiving said firstmedical image comprises: receiving a film-based image of said anatomicalpart of the human body; and digitizing said film-based image to formsaid first medical image.
 46. The method of claim 41, furthercomprising: determining whether said destination device is capable ofreceiving and processing DICOM CAD Structured Report Information ObjectInstances (CAD SR-IOIs); and if said destination device is capable ofreceiving and processing DICOM CAD SR-IOIs, incorporating informationrelating to said detected anatomical abnormalities into a CAD SR-IOI andtransmitting same to said destination device.
 47. The method of claim46, further comprising performing said forming and said transferring ifsaid destination device is not capable of receiving and processing DICOMCAD SR-IOIs.
 48. A machine readable storage medium having stored thereonmachine executable instructions, the execution of said machine readableinstructions to implement a method comprising: forming a secondary imageof a body part having one or more CAD markers fixably integrated thereinidentifying one or more CAD-detected abnormalities in the body part,wherein said secondary image is of a standard DICOM image type notspecified for CAD results; and transferring said secondary image to adestination device according to the DICOM protocol.
 49. The machinereadable storage medium method of claim 48, wherein said secondary imagecomprises a DICOM Secondary Capture image.
 50. The machine readablestorage medium of claim 48, wherein said destination device comprises aDICOM-conforming device selected from the group consisting of: a viewingworkstation, an image archiving system, and a hardcopy printer.
 51. Themachine readable storage medium of claim 48, the method furthercomprising: receiving a Source Image Information Object Instance from aDICOM-conforming source device, the Source Image Information ObjectInstance comprising a primary image of the body part; and processing theprimary image to identify the CAD-detected abnormalities in the bodypart.
 52. The machine readable storage medium of claim 51, wherein saidprimary image is of diagnostic quality, and wherein said secondary imageis of less-than-diagnostic quality.
 53. The machine readable storagemedium of claim 48, the method further comprising: receiving afilm-based image of the body part; digitizing said film-based image toform a primary image; and processing the primary image to identify theCAD-detected abnormalities in the body part.
 54. The machine readablestorage medium of claim 53, wherein said primary image is of diagnosticquality, and wherein said secondary image is of less-than-diagnosticquality.